Hydraulic pumping jack with control responsive to abnormal conditions



May 17, 1949. s. c. KYLE 2,470,252

HYDRAULIC PUMPING JACK KITH" CONTROL RESPONSIVH TO ABNORMAL CONDITIONS Filed Nov) 9, 1945 5 Sheets-Sheet 1 S MUEL CLYDE KYLE ATTOPNE Y5 HYDRAULIC PUMIING JACK WITH CONTROL May 17, 1949. s c. KYLE 2,470,252

RESPONSIVE TO ABNORMAL CONDITIONS Filed NOV. 9, 1945 5 Sheets-Sheet 2 SAMUEL CLYDE KYLE A TTORNE Y5 May 17, 1949. s. c. KYLE 2,470,252

HYDRAULIC PUMPINGJACK WITH CONTROL 7 RESPONSIVE T0 ABNORMAL CONDITIONS I Filed Nov. 9, 1945 3 Sheets-Sheet 3 INVENTOR. 5AMUEL CL YUE KYLE a zwwm ATTORNEYS Patented May 17, 1949 HYDRAULIC PUMPING JACK WITH CON- TROL RESPONSIVE TO ABNORMAL CON- DITIONS :Samuel Clyde Kyle, Berkeley, Calif.,-assignor vto The Pelton Water Wheel Company, San Francisco, Calif., a corporation of California Application November 9, 1945,. Serial No. 627,597

6 Claims.

This invention relates in general to a hydraulic deep well pumping jack system including a hydraulic jack; a balancin pressure tank, a constant displacementmain pump and an automatic control valve. The balancing pressure tank of the system is maintained at a pressure such that the resulting lifting force of the pressure applied in the hydraulic jack equals the rod weight plus one-half of the fluid weight normally lifted by the jack. The main operating pump and control valve are disposed between the jack and the balancing tank so that operation of the main pump and control valve to produce flow from the tank to the jack will'lift'the pistonin the jack cylinder while operation of thelmain pump and control valve to produce flow from the jack to the tank will lower the piston in the jack cylinder. A special hydraulic control mechanism is provided automatically to reverse the action as the vjack piston reaches the terminal point at each end of the stroke. By maintaining the pressure in the balancing tank as described above, the main pump is subjected to a substantially constant load during the upstroke and downstroke of the jack. During the upstroke the main pump must develop sufficient pressure which when applied to the jack will augment the balancing tank pressure and lift the entire rodplus the fiuidload. Conversely, during the downstroke, the main pump must suificiently reduce the'pressure within the jack so as toremove fluid from the jack so that the load on the jack will bereducedto the rod load'only.v Associated with and forming an integral part of this system is a drain system for returning fluid from the upper end of the hydraulic jack cylinder and from the control and pilot valves to the lower end of the balancing pressure tank.

. Normallythe drain system is maintained at or slightly below atmospheric pressure by means of a scavenging pump and suitable check valves in serted in the drain lines and serves to return leakage and loW-pressure-fluid to the balancing pressure tank thereby retaining it in the system. Under certain conditions,.however, fluid delivered to the drain system may exoeed'the capacity of the scavenging pump to return such fluid to the tank. The resulting back pressure on the jack piston and the control and; pilot valves will then arise, hindering the general operation and if high enough causin a hydraulic lockout of. the whole system.

In general, the object of thisinvention is the provision in a pumping jack system of the characterdescribed of a-valve automatically responsive to any excessive pressure in the drain for establishing communication between the pressure and suction sides of the main pump.

Another-object of this invention is to reduce the operation of the-mainpumping system when an abnormal condition occurs in the drain pumping system.

Another object of this invention is in general to improve pumping jacks.

The invention possesses other advanta eous features, some of which with the foregoing will be set forth at length in the following description where that form of the invention, whichhas been selected for illustration in the drawings accompanying-and forming a part of the present specification, is outlined in full. In said drawings, one form of the invention is shown, but it is tobe understood that it is not limited to such form, since the invention, as set forth in the claims, may be embodied-in a-plurality of forms.

' Referring to the drawings:

Fig. 1 diagrammatically illustrates a hydraulic jack system embodying the invention and shows the system in the upstroke position of the hydraulic jack.

Fig. 2 is a view similar to Fig. 1 but shows the system in the downstroke position of the jack.

Fig. 3 is an enlarged longitudinal section of the relief valve formingpart of the system illustratedin Figs. 1 and 2.

In general, the system shown in these figures includes a hydraulic jack A, the piston of which carries a polished rod; a balancing pressure tank B, maintained at a pressure suflicient to produce a lifting load in the jack equal to the rod load plus one-half of the fluid load supported by the jack; a constant displacement main pump C capable of producing a pressure above the tank pressure sufficient to lift the rod weight plus the fluid weight, andsalso capable. of reducing the pressure in the jack below the pressure in the balancing tank so as to permit the sucker rod to drop; a main control valve D, disposed between the main pump and the balancing pressuretank for alternately delivering fluid from the pressure tank to the hydraulic jack on the upstroke of the jack and then from the jack to the tank on the downstroke of the jack; a pilot valve E; responsive differentially and hydraulically to the terminal movements of the hydraulic jack piston for operating the main control valve; and a normally closed relief valve F for establishing communication between the discharge and suction of the main pump in response to any excessive pressure in the drain system.

As disclosed in Figs. 1 and 2, the hydraulic jack A includes a cylinder I, with which is operatively associated a piston 2. Depending from the piston 2 through a suitable stuffing box in the lower end of the cylinder I, is a polished rod 3, to which is fastened the sucker rod of an oil well pump. The cylinder l is provided on its lower end with a fluid inlet and outlet port 4 and at its upper end with a, fluid outlet port 5 communicating through a check valve 6, a line i and a check valve 8 with an intake port 9 provided in the lower end of the cylinder above the port 4. Also provided in the upper end of the cylinder i are a pair of longitudinally spaced outlet drainage ports H and i2, communicatin through a drain circuit including a line 53, a check valve I4, a line I5, a scavenging pump I6, a line I'l, a check valve I8 and a line I5 with an intake port 2| provided in the lower end of the balancing pressure tank B.

The main pump C is of the constant displacement type, including a pair of opposed suction chambers 22 and 23 and a discharge compartment 24 with a discharge outlet 2's and with a relief valve outlet 28 communicating through the relief valve F with an inlet port 29 associated with the suction chamber 23.

The main control valve D is of the piston type including a main cylinder 32 provided with five longitudinally spaced annular channels 33, 34, 35, 35 and 37. Provided on either end of the valve D, coaxially with the main cylinder 32, are smaller cylinders 38 and 39. Operatively associated with the main cylinder 32 are a pair of longitudinally spaced pistons 45 and 42 mounted on a piston shaft 43, and carried on the ends of the shaft 43 are pistons 44 and 45 operatively associated with the cylinders 38 and 39. The simultaneous movement of the pistons 4|, 42, 44 and 45 from their positions as shown in Fig. 1 to the positions shown in Fig. 2 is effected through the pilot valve E in a manner which will be described later in connection with the description of the valve E. The annular channel 36 communicates through a port 36a, a line 45 and a line 47 with a port lla provided in the lower end of the tank B. Fluid from the tank B passes through the port 41a, the line 47, the line 46, and the port 36a into the channel 35. From this channel the fluid passes into the channel 31, through a port 31a associated with the channel 3'! and through a line 4-8 and the inlet port 26 into the suction chamber 23. The line 48 communicates through a line 49 with a line 5| which, in turn, communicates with the inlet port 25 of the suction chamber 22 and with a port 33' associated with the annular chamber 33. It will, therefore, be seen that the fluid passing through the channels 36 and 3? of the main control valve will be delivered to both of the suction chambers 22 and 23 of the main pump C. The main pump C then delivers this fluid through its outlet port 27!, through a line 52 and a port 35a associated with the channel 35 into the channel 35. From the channel 35, the fluid passes through the channel 34, through a port 3411 associated with this channel and through a line 53 and the port 4, into the lower end of the cylinder I. In this position or condition of the hydraulic circuit the main pump C operates to pass fluid from the tank B through the main control valve D into the lower end of the cylinder I', thereby to raise the piston 2.

Any fluid which may have moved upwardly past the piston 2 is delivered through the ports II and I2, the line I3, the check valve I4, the line I5, the scavenging pump I6, the line I1, the check valve I8, and the line I9 through the port 2I associated with the lower end of the tank B into the tank B. This drain circuit thus returns such fluid to the tank B as a reservoir. In this connection, it should be noted that the scavenging pump I6 is operated so as normally to maintain substantially atmospheric pressure on the check valve I4 and in the line I5.

When the piston 2 rises above the port 5, fluid under the main pump pressure passes through the port 5, the check valve 6, the upper portion of the line i, and the line 54 to the left end port 55 associated with the pilot valve E.

The pilot valve E is of the same type as the main control valve D, and includes a main cylinder 56 with which are operatively associated three longitudinally spaced coaxial pistons 51, 58 and 59, fastened to a common shaft 6|. Formed on the right end of the pilot valve E is a cylinder 62 of a smaller diameter than the main cylinder 58 and provided with an outlet port 63. Operatively associated with the cylinder 62 is a piston 64, fastened to or forming a continuation of the right end of the shaft 6!. Communication between the port 63 and the port 331) associated with the channel 36 of the main control valve D, is established by a line 65. With the main valve in the position as shown in Fig. 1, fluid from the tank B is delivered from the channel 36 through the line 65 to the smaller cylinder 52. However, since the area of the piston 64 is less than the area of the piston 51, the fluid pressure in the line 54 will cause the pistons 51, 58, 59 and 64 to move to the right to assume the position shown in Fig. 2.

With the pilot valve E in the position as shown in Fig. 2, and the main control valve in the position as shown in Fig. 1, fluid under tank pressure passes upwardly through the line 46, the port 36b, the line 66, the valve E and the line 61 into the left end cylinder 38 of the main valve D to force the pistons 4|, '42, 44 and 45 to the right, as shown in Fig. 2. Due to the right hand movement of the piston 45, fluid contained in its cylinder 39 passes through a drain circuit including a line 66, the pilot valve E, and a line 69, line H, to the drain line I5 from which the pressure is increased by the scavenging pump I6 sufficient to restore the fluid to the bottom of the tank B through the check valve I8.

With main valve D, as well as pilot valve E, in the positions as shown in Fig. 2, the main pump C operates to draw liquid from the lower end of the hydraulic jack cylinder I', through the port 4, upwardly through the line 53, through the intercommunicating ports 34a and 33a of the main control valve D, and into the suction chambers 22 and 23 of the main pump. The main pump then operates to deliver this fluid from its discharge compartment 24 through the intercommunicatin ports 35a and 36a of the main control valve D, the line 46 and the port 41a to the lower end of the balancing tank B.

When the piston 2 of the hydraulic jack passes the port 5 on its downward stroke, no efiect is produced on the pilot valve E because the check valve 6 does not permit the flow of fluid back into the cylinder I. When, however, the piston 2 passes the port 9 on its downward stroke, the port 55 of the pilot valve E is placed in communication through line I, the line 54, the check valve 8, the cylinder I, the line I3, the check valve 14; the scavenging pump I6 and the check valve I8 with the lower end OfZ'thLGZ tank B. floncurrently the right hand end: ofthe'small 'piston 6t ot ithe pilotvalve subject to tank pressure through the interconnecting ports 38b and 316m of the main control'valve D and throughthe line '65. Since at this point in the cycleof operation the left endof the piston 57 is under the influence of substantially atmospheric pressure, the tank pressure on the piston 64 moves it to the left, whereby the pilot valve E assumes its original position as shown in Fig. 1. In this latter position, or condition of the system, fiuid under tank pressure passes through the lines 4'! and 46, the intercommunicating ports 36a and *36b of the main valve, the line 98, the intercommunicating portsTS. and 12 of the pilot valve and the line 68 to. the right end cylinder 39 of the main valve. Since the left end piston 44 of this valve is new in'communication with the drainsystem through the line 61, the intercommunicating ports 14 and 15 of the pilot valve, the line 69 and the line H, the tank pressure on the piston 45 results in moving this piston and its associated pistons to the left to assume their original position as shown in Fig. l. The system so far described is in condition to repeat the complete cycle of operation as above disclosed.

The valve F comprises a flanged section 16 provided with a port 71, communicating through a line 18 with the port 28 of the main pump C, and with a port 19, communicating through a line 8| with the port 29 of the main pump. Connected to the flanged section 16 is a central section 82 provided with a port 83, communicating through a, line 84 and a three-way valve 85 with the line H, and with a port 86 communicating through a check valve 81, with the three-Way valve 85 and through a relief valve 88 and a line 89 to an atmospheric drain. Threaded to the central section 82 is an end section 9| forming a cylinder 92 for the reception of a hollow piston 93. Provided intermediate the ends of the piston 93 is a section 94 of enlarged diameter, operatively associated with a cylinder 95 formed in the central section 82. Disposed within the piston 93 and seated against its lower closed end 96 is a spring 91. Seated on the upper end of the spring 9'! is a flanged ring 98 formed with a central opening 99, and contacting the ring 98 is an adjustment screw l! extending through the upper end of the piston 93 and threaded through the upper end of the casing section 9|. The casing section 16 is provided intermediate its ports 11 and 19 with a seat I02 on which the lower end 96 of the piston 93 seats normally to close off communication between the ports I1 and 19.

The piston 93 is formed with ports Hill which provide communication between the port 19 and the end of the cylinder 92 above the piston end 96. Accordingly, as long as operating conditions are normal, the opposite sides of piston 93 are subjected to the difierential pressure of the main pump C. As the main pump discharge is normally always above the main pump suction pressure, the piston 93 is maintained in its closed position under normal operation by means of the spring 91. If the operating diiferential on the main pump C exceeds normal limits, the valve will open so as to by-pass fluid from the port 11 to the port 19 and thereby relieve the excessive pressure.

In addition to normal relief valve operation, added protective features are incorporated in the valve through the connection from the port 83 :to 'thedrain' line 5 so that if excessive pressure should develop in thedrain line 15, that'pres'sure will be exerted on the lower side ofthe piston section 93 so as to overcome the hydraulic and spring balance of the piston 93 and thereby elevate the piston to establish communication betweeai the'pressure and :suctionsides ofthe main fails gradually'to restore the system to normal operating conditions as the valve F slowly closes in response to the pressure drop due to the gradual removal of the excess oil from the drain system. A hydraulic lockout of the entire mechanism: is thereby forestalled :by slowing. up operation of the-main pumping system until the abnormal condition that would otherwise produce a lookout is overcome.

I claim:

1. A hydraulic pumping jack system comprising: a hydraulic jack; a balancing pressure tank; a pumping system having a pump for delivering fluid alternately from said tank to said jack on the upstroke of said jack and from said jack to said tank on the downstroke of said jack; a drain system for returning drain fluid from the hydraulic jack and pumping system to said tank at a predetermined pressure; a normally closed valve disposed between the low and high pressure sides of said pump; and means for opening said valve in response to abnormally high pressures in said drain system to establish communication between the discharge and suction sides of said pump.

2. A hydraulic pumping jack system comprising: a hydraulic jack; a balancing pressure tank; a pumping system having a main pump for delivering fluid alternately from said tank to said jack on the upstroke of said jack and from said jack to said tank on the downstroke of said jack; a drain system including a scavenging pump for returning drain fluid from the hydraulic jack and pumping system to said tank at a predetermined differential pressure; and a normally closed relief valve connected to the low and high pressure sides of said main pump, said valve being responsive to an excessive scavenging pump differential pressure so as to establish communication between the discharge and suction sides of said main pump.

3. A hydraulic pumping jack system comprising: a hydraulic jack; a balancing pressure tank; a pumping system having a pump, and a control valve in circuit with said pump, said tank and said jack and effective in one position to connect said pump to deliver fluid from said tank to said jack during the upstroke of said jack and in another position to connect said pump to deliver fluid from said jack to said tank during the downstroke of said jack; a drain system for delivering drain fluid from said jack and said pumping system to said tank at a predetermined pressure; and a Valve responsive to an excessive pump differential pressure I and to pressures in said drain system in excess of said predetermined pressure for establishing direct communication between the high and low pressure sides of said pump.

4. A hydraulic pumping jack system comprising a hydraulic jack; a balancing pressure tank; a hydraulic circuit interconnecting said jack and said tank; a pump in said circuit for interchang-' ing fluid between said jack and said tank; a drain circuit for conducting fluid from said hydraulic circuit to said tank; and means responsive to pressure in said drain circuit for reducing the interchanging of said fluid by said pump.

5. A hydraulic pumping jack system comprising a hydraulic jack; a hydraulic reservoir; a hydraulic circuit for interconnecting said jack and said reservoir; a main pump in said hydraulic circuit; drain circuit for conducting fluid from said hydraulic circuit to said reservoir; a relief valve responsive to pressures in said hydraulic circuit for connecting the outlet of said main pump directly to the inlet thereof; and means responsive to pressures in said drain circuit for augmenting the effect of pressures in said hydraulic circuit upon said valve.

6. A hydraulic pumping jack system comprising a hydraulic jack; a hydraulic reservoir; a

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,185,448 Suter Jan. 2, 1940 2,303,628 Geiger Dec. 1, 1942 2,325,138 Kyle July 27, 1943 2,367,248 Vickers Jan. 16, 1945 

